How to transmit data over long distances using WiFi

Hey all,

I previously posted this in networking as I didn't see this channel.

I am pretty new to all this so if you have any tips/links/etc to share please do as they will all be very much appreciated.

My goal is to collect data from various sensors based around my property (farm).

I have found the Flutter wireless chip (http://flutterwireless.com) that has 1km line of sight wifi however some of the sensors will be up to 6km away and are not line of sight.

This means that I will need multiple points to relay the data along. I realise that I could set up multiple Raspberry Pis to collect and transmit the data but as everything will need to be solar powered I was hoping to achieve it with Arduinos.

Cheers, Damian

The Raspberry Pi doesn't ship with any in-built wireless capabilities.

The first thing to consider is choosing an operating frequency that is legal in your country. The Flutter device uses 915MHz. In my country this has been allocated to the cellular phone companies who pay large licensing fees to the government, and will come knocking on your door if you cause interference.

6 km, with no line of sight, is extremely difficult for an unlicensed wireless operation. I am under the impression that it is very difficult to get over 1 km line of sight range for any commercially available modules that operate in the unlicensed bands, so you will have to consider several repeaters, each one failure prone.

You may know about the this NZ installation, but that is 300 m and line of sight, which is pretty trivial.

6km is a stretch for tinkering with anything, so you might as well use GPRS shields, secure in the knowledge that you can get it right first time, no relaying required, and you can actually stay on the right side of the law.

Another option is satellite. For very limited data uploads, the RoadBlock system is surprisingly inexpensive.

That has the advantage that you don't have to mess with several repeaters, it works anywhere in the world, and your data automatically end up on the web.

Please do not cross-post. Other thread removed.

A Google search for "2.4 ghz mesh network" or "ism mesh network" has quite a few results.

If you use directional antenna like Yagi antenna for the WiFi on both side, you may get 6kM point-to-point.

If you need better gain you can try parabolic antenna, people had used it for 110kM line of sight on the hill top.

Check out this long range radio system
50KM Long Range FPV Rlink 433Mhz 16 Channel 1W FPV UHF System Transmitter w/8 Channel Radio Receiver

These folks advertise a license free mesh network of small, low power modules, and claim up to 700 meters per hop.

BillHo: If you use directional antenna like Yagi antenna for the WiFi on both side, you may get 6kM point-to-point.

Boosting a signal above the legally allowable ERP is not a good idea. As this is the ISM band the government won't care but your neighbours may ask questions.

You could use a network of Zigbee or maybe even Xbee modules to get the coverage.